How much brutality can you take from a movie? How much is too much? How many scenes of pain, suffering and bloodletting can you stand before you throw up your hands and cry uncle? With The Nightingale, her follow-up to the horror hit The Babadook, director Jennifer Kent seems to posing those direct questions to the audience. The filmmaker knows that we, as a species, have a thirst for violence. But that thirst has its limits. Kent wants to push beyond those limits, and then keep going. And then go further. And then ask, “Isn’t this what you wanted? Why so squeamish now?” As an experiment, it’s fascinating. As a film, it’s almost too much to stand.